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			373 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			373 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
/*
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 *  armboot - Startup Code for ARM926EJS CPU-core
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 *
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 *  Copyright (c) 2003  Texas Instruments
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 *
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 *  ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
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 *
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 *  Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
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 *  Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
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 *  Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
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 *  Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
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 *  Copyright (c) 2003	Kshitij <kshitij@ti.com>
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 *
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 * See file CREDITS for list of people who contributed to this
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 * project.
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU General Public License as
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 * published by the Free Software Foundation; either version 2 of
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 * the License, or (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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 * MA 02111-1307 USA
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 */
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#include <config.h>
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#include <version.h>
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/*
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 *************************************************************************
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 *
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 * Jump vector table
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 *
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 *************************************************************************
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 */
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.globl _start
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_start:
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	b	reset
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	ldr	pc, _undefined_instruction
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	ldr	pc, _software_interrupt
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	ldr	pc, _prefetch_abort
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	ldr	pc, _data_abort
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	ldr	pc, _not_used
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	ldr	pc, _irq
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	ldr	pc, _fiq
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_undefined_instruction:
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	.word undefined_instruction
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_software_interrupt:
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	.word software_interrupt
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_prefetch_abort:
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	.word prefetch_abort
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_data_abort:
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	.word data_abort
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_not_used:
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	.word not_used
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_irq:
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	.word irq
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_fiq:
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	.word fiq
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	.balignl 16,0xdeadbeef
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/*
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 *************************************************************************
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 *
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 * Startup Code (reset vector)
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 *
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 * do important init only if we don't start from memory!
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 * setup memory and board specific bits prior to relocation.
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 * relocate armboot to ram
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 * setup stack
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 *
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 *************************************************************************
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 */
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_TEXT_BASE:
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	.word	TEXT_BASE /* address of _start in the linked image */
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.globl _armboot_start
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_armboot_start:
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	.word _start
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/*
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 * These are defined in the board-specific linker script.
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 */
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.globl _bss_start
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_bss_start:
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	.word __bss_start
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.globl _bss_end
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_bss_end:
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	.word _end
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#ifdef CONFIG_USE_IRQ
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/* IRQ stack memory (calculated at run-time) */
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.globl IRQ_STACK_START
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IRQ_STACK_START:
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	.word	0x0badc0de
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/* IRQ stack memory (calculated at run-time) */
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.globl FIQ_STACK_START
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FIQ_STACK_START:
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	.word 0x0badc0de
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#endif
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/*
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 * the actual reset code
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 */
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.globl reset
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reset:
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	/*
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	 * set the cpu to SVC32 mode
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	 */
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	mrs	r0,cpsr
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	bic	r0,r0,#0x1f
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	orr	r0,r0,#0xd3
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	msr	cpsr,r0
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	/*
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	 * we do sys-critical inits only at reboot,
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	 * not when booting from ram!
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	 */
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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	bl	cpu_init_crit
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#endif
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relocate:				/* relocate U-Boot to RAM	    */
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	adr	r0, _start		/* pc relative  address of label    */
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	ldr	r1, _TEXT_BASE		/* linked image address of label    */
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	cmp	r0, r1                  /* test if we run from flash or RAM */
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	beq	stack_setup             /* ifeq we are in the RAM copy      */
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	ldr	r2, _armboot_start
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	ldr	r3, _bss_start
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	sub	r2, r3, r2		/* r2 <- size of armboot            */
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	add	r2, r0, r2		/* r2 <- source end address         */
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copy_loop:
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	ldmia	r0!, {r3-r10}		/* copy from source address [r0]    */
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	stmia	r1!, {r3-r10}		/* copy to   target address [r1]    */
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	cmp	r0, r2			/* until source end addreee [r2]    */
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	ble	copy_loop
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	/* Set up the stack						    */
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stack_setup:
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	ldr	r0, _TEXT_BASE		/* upper 128 KiB: relocated uboot   */
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	sub	r0, r0, #CONFIG_SYS_MALLOC_LEN	/* malloc area                      */
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	sub	r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo                        */
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#ifdef CONFIG_USE_IRQ
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	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
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#endif
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	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
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clear_bss:
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	ldr	r0, _bss_start		/* find start of bss segment        */
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	ldr	r1, _bss_end		/* stop here                        */
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	mov	r2, #0x00000000		/* clear                            */
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clbss_l:str	r2, [r0]		/* clear loop...                    */
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	add	r0, r0, #4
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	cmp	r0, r1
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	ble	clbss_l
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	ldr	pc, _start_armboot
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_start_armboot:
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	.word start_armboot
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/*
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 *************************************************************************
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 *
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 * CPU_init_critical registers
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 *
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 * setup important registers
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 * setup memory timing
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 *
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 *************************************************************************
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 */
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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cpu_init_crit:
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	/*  arm_int_generic assumes the ARM boot monitor, or user software,
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	 * has initialized the platform
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	 */
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	mov	pc, lr		/* back to my caller */
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#endif
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/*
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 *************************************************************************
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 *
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 * Interrupt handling
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 *
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 *************************************************************************
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 */
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@
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@ IRQ stack frame.
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@
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#define S_FRAME_SIZE	72
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#define S_OLD_R0	68
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#define S_PSR		64
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#define S_PC		60
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#define S_LR		56
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#define S_SP		52
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#define S_IP		48
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#define S_FP		44
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#define S_R10		40
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#define S_R9		36
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#define S_R8		32
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#define S_R7		28
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#define S_R6		24
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#define S_R5		20
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#define S_R4		16
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#define S_R3		12
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#define S_R2		8
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#define S_R1		4
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#define S_R0		0
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#define MODE_SVC 0x13
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#define I_BIT	 0x80
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/*
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 * use bad_save_user_regs for abort/prefetch/undef/swi ...
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 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
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 */
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	.macro	bad_save_user_regs
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	@ carve out a frame on current user stack
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	sub	sp, sp, #S_FRAME_SIZE
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	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12
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	ldr	r2, _armboot_start
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	sub	r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
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	sub	r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8)  @ set base 2 words into abort stack
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	@ get values for "aborted" pc and cpsr (into parm regs)
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	ldmia	r2, {r2 - r3}
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	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
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	add	r5, sp, #S_SP
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	mov	r1, lr
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	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
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	mov	r0, sp		@ save current stack into r0 (param register)
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	.endm
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	.macro	irq_save_user_regs
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	sub	sp, sp, #S_FRAME_SIZE
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	stmia	sp, {r0 - r12}			@ Calling r0-r12
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	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
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	add	r8, sp, #S_PC
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	stmdb	r8, {sp, lr}^		@ Calling SP, LR
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	str	lr, [r8, #0]		@ Save calling PC
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	mrs	r6, spsr
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	str	r6, [r8, #4]		@ Save CPSR
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	str	r0, [r8, #8]		@ Save OLD_R0
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	mov	r0, sp
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	.endm
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	.macro	irq_restore_user_regs
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	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
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	mov	r0, r0
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	ldr	lr, [sp, #S_PC]			@ Get PC
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	add	sp, sp, #S_FRAME_SIZE
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	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
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	.endm
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	.macro get_bad_stack
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	ldr	r13, _armboot_start		@ setup our mode stack
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	sub	r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
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	sub	r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
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	str	lr, [r13]	@ save caller lr in position 0 of saved stack
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	mrs	lr, spsr	@ get the spsr
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	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
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	mov	r13, #MODE_SVC	@ prepare SVC-Mode
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	@ msr	spsr_c, r13
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	msr	spsr, r13	@ switch modes, make sure moves will execute
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	mov	lr, pc		@ capture return pc
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	movs	pc, lr		@ jump to next instruction & switch modes.
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	.endm
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	.macro get_irq_stack			@ setup IRQ stack
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	ldr	sp, IRQ_STACK_START
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	.endm
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	.macro get_fiq_stack			@ setup FIQ stack
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	ldr	sp, FIQ_STACK_START
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	.endm
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/*
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 * exception handlers
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 */
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	.align  5
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.globl undefined_instruction
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undefined_instruction:
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	get_bad_stack
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	bad_save_user_regs
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	bl	do_undefined_instruction
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	.align	5
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.globl software_interrupt
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software_interrupt:
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	get_bad_stack
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	bad_save_user_regs
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	bl	do_software_interrupt
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	.align	5
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.globl prefetch_abort
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prefetch_abort:
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	get_bad_stack
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	bad_save_user_regs
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	bl	do_prefetch_abort
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	.align	5
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.globl data_abort
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data_abort:
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	get_bad_stack
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	bad_save_user_regs
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	bl	do_data_abort
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	.align	5
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.globl not_used
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not_used:
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	get_bad_stack
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	bad_save_user_regs
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	bl	do_not_used
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#ifdef CONFIG_USE_IRQ
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	.align	5
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.globl irq
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irq:
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	get_irq_stack
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	irq_save_user_regs
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	bl	do_irq
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	irq_restore_user_regs
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	.align	5
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.globl fiq
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fiq:
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	get_fiq_stack
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	/* someone ought to write a more effiction fiq_save_user_regs */
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	irq_save_user_regs
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	bl	do_fiq
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	irq_restore_user_regs
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#else
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	.align	5
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.globl irq
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irq:
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	get_bad_stack
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	bad_save_user_regs
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	bl	do_irq
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	.align	5
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.globl fiq
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fiq:
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	get_bad_stack
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	bad_save_user_regs
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	bl	do_fiq
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#endif
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